Spring drive apparatus



Dec. 8, 1959 G. w. scoTT Erm. A2,915,906

SPRING DRIVE APPARATUS Filed Nov. 1. 1957 l 2 Sheets-Sheet 1 "Il di WMnu 33 Dec. 8, 1959 G. w. sco'rT ETAL SPRING DRIVE APPARATUS 2Sheets-Sheet 2 Filed Nov.` 1. 1957 United States Patent O SPRING DRIVEAPPARATUS George W. Scott and William R. Maclay, Endicott, N.

assignors to International Business Machines Corporation, New York,N.Y., a corporation of New York Application November 1, 1957, Serial No.694,025 Claims. (Cl. 74-125.5)

This invention relates to spring drive apparatus and particularly to anarrangement whereby an output shaft has a relatively constant torqueavailable for intermittent use or continuous use at a variable rate.

In the prior art, a number of devices of the spring drive type areknown. The best known, perhaps, are spring drive devices wherein awinding mechanism may be periodically operated to wind a spring which isconnected in a fashion to supply torque to an output shaft. Onedisadvantage of such apparatus is that the torque available to do workis non-linear in nature between the time the spring is completely woundand the time it is ready to be rewound. A further disadvantage oftheprior art devices is that they are bulky in size, thereby making theiruse in a limited space a handicap in many applications. In contrast, thepresent invention is a compact and quite small apparatus for producing asubstantially constant torque available at an output shaft. Acontinuously running input shaftY is intermittently connected to wind aspring only when it is necessary to do so in order to provide theaforementioned constant torque. A low r.p.m., variable torque motor maybe utilized as an input drive for the spring and the torque available atthe output shaft may be released intermittently for variable intervalsof time with constant torque, high acceleration, and low moment ofinertia.

A primary object of the present invention is to furnish a new andimproved spring drive or spring motor arrangement for providing asubstantially constant torque available at an output shaft.

Another object of the invention is to provide a new and improvedarrangement for coupling a continuously running input shaft to wind aspring only when there is an indication that the spring needs to bewound in order to provide a substantially constant torque to an outputshaft.

Still another object of this invention is to furnish a new and improvedarrangement as described above which is compact in size and utilizes aminimum of parts.

Other objects of the invention will be pointed out in the followingdescription and claims and illustrated in the laccompanying drawings,which disclose, by way of examples, the principle of the invention andthe best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a cross-sectional view of the present invention showing theinput drive motor clutched to wind the spring:

Fig. 2 is a fragmentary view of Fig. 1 showing the clutch in itsinoperative position;

Fig. 3 is aview taken on lines 3-3 of Fig. 1; and

Fig. 4 is a View taken on lines 4-4 of Fig. 1.

Similar reference numerals represent similar parts throughout theseveral views.

Briey, the present invention comprises a spiral storage spring connectedin a fashion to provide a torque to an output shaft. Winding of thespring is accomplished by way of a clutching arrangement comprising ahollow shaft connected to one end of the storage spring and periodicallyclutched to the input drive motor by way of an expanding helical springclutch. The clutch is disengaged by means of a movable member whichdetermines when the storage spring is wound. When a predetermined amountof rotation of the output shaft has occurred, the movable member permitsthe clutch to be reengaged so that winding of the storage spring beginsagain.

For a more detailed description of the invention, reference is made toFigs. l through 4. A cylindrical housing 10 is provided with a mountingange 11 at one end thereof, the said flange being provided withapertures for mounting in a suitable frame (not shown). The housing isprovided with a cylindrical bore 13 which is countersunk to provide anannular recess 12, thereby providing a shoulder 14 between the annularrecess 12 and the cylindrical bore 13.

The outer race of a bearing 15 is adapted to have a pressure tit in theannular recess 12, the inner race of the bearing being secured to acollar 16. In this fashion, the collar 16 is journalled for rotation inthe housing 10 and serves as an input shaft. A gear 17 is formedintegrally with the collar 16 at one end thereof, said gear having teethon the periphery thereof that are adapted to mesh with a gear 1S whichis driven by a suitable motor 19.

A bearing 20 is mounted in an annular recess in collar 16 and isutilized to journal one end of a hollow shaft 21 for rotation withincollar 16. A sleeve bushing 22 is keyed to the hollow shaft 21 forrotation therewith. Bushing 22 is prevented from axial movement relativeto the hollow shaft 21 by retaining rings 23 and 24 which t in suitablegrooves in the hollow shaft. Bushing 22 is journalled by means of abearing 25 for rotation relative to housing 10, bearing 25 being securedto housing 10 in the bore 13 and having a portion thereof in abuttingrelationship to shoulder 14 between the annular recess 12 and bore 13.

A cylindrical extension 26 is provided integral with bushing 22, theextension having an annular recess 27 formed therein which is of thesame diameter as the inner surface 28 of collar 16. An expanding typehelical spring clutch 29 is situated between the outer surface of thehollow shaft 21 and the inner surfaces 27 and 28. Since the helicalspring 29 is urged to expand, it is normally urged against surfaces 27and 28. This causes the continuously running collar 16 to be clutched tothe hollow shaft 21 by way of the cylindrical extension 26 and thebushing 22.

One end of helical spring 29 is turned in to form a finger 30 which isadapted to engage an axially extending rib 31 on an internally threadedelongated sleeve 32. The other end of the spring is adapted to enter ahole in bushing 22 so as to be held in fixed relation thereto. Thissleeve might be characterized as an elongated nut since it performssomewhat the same function. The sleeve or nut 32 is adapted to fitwithin the hollow shaft 21 and to have axial movement relative thereto.A slot 70 is furnished in the hollow shaft 21 and is adapted to receiverib 31 therein, said slot permitting limited rotational and axialmovement of nut 32 within the hollow shaft.

The output shaft 34 Ais provided with a threaded portion 33 which isreceived by the internal threads of nut 32. Thus, the output shaft isallowable to rotate within nut 32. While the output shaft is allowed torotate, it is not permitted axial movement relative to the cylindricalhousing 10. The left end of the output shaft, as seen in Fig. l, isjournalled in a hub 36 by means of a suitable bearing 35 retaining ring37 is arranged adjacent hub 36 and stud Patented Dec. 8, 1959 Y i i'leftand will fstop rotating :collar 16. A tthis time, the Ystoragespring can begin. ,Y Y.Itlrwill be Vseen fromthevabove that evenafterftheref v'I sg., bolts 38 are vused to secure' both the hub andretaining ring to the cylindrical housing 10.

Hub 36 has an annular surface 71 having the same diameter as the annularsurface of the hollow shaft 21, there beingfurnis'heda helicalv springbrake40 which is .adapted to'iit over these surfaces. Spring 40'has oneend portion` thereof clamped to surface 71V by means of a ring'` 39.

This spring is ofthe type used asone way brakes. That is, sleeve 21 isallowedto rotate freely in one direction relative to hub' 36 butisprevented from rotation in the reverse direction. This type of springbrake is well known,v andiis used extensively for the purposedescribedherein: If sleeve 21 isrotated Vin a direction such thatzth'e frictionbetween'thesleeve surface'and the spring tends to urge anincreasein'diameter'ofthe spring, the sleeve isY allowed to rotatefreely.' VHowever, when-the 4reverse rotation is attempted,Vthe:frictionaforementioned urges the spring* to contract so `that afriction iscreated between the spring v andlsleeve whichcannotjbe'overcome. f Y

Asfshown in' Fig. l, thetraveling nut 32 is' provided with a lug 41which projects from the left side thereof.. A lug 42 is also V,furnishedon the inside of hub 36and isadapted to`b`eiengagedbyV lug. 41 when thetravelling nut 32 is` moved tothe left to its limit of travel. L

Atfthe'right'end Aof the hollow shaft 21V, as seen in Fig.

l, a housing 43 is formed. A This housing is comprised of aside 44 whichis in the form of a ange on the end ofthe hollowshaftfpZl, acylindricalportion' 45 integralwith" the'periph'eral edge of Vside 44,and acover plate or disc' 46 which forms the ptherside of the housing.Themernber` 46isfapertured, as at 47, to receivethe portion 48 of the ioutput shaft; ABetween the threadedportion 33 and portion A43` of theoutputshaft, an enlarged portion 49 is formed .whichy lits vwithin thehousing.

j The storage kspring 50Vis aj spiral spring having one endlargedportion 49 of the output shaft by a screw 52. l The operationofthe invention will .now be described in detail.

spring Yclutch .29 will berexpanded against' the inner surfaces 27 and28 of members 26' and 16`,frespectively. Therefore, bushing 22, hollowshaft 21 and housing 43 vwill allV rotate withthecontinuously rotatingcollar 16 which. is driv'enby themotor 19. Since 'spiral spring clutch29V also rotatesythrough the members 16 and 22, theinger 30,

"whic h engagesrib 31 on a travelling nut 32, .causes the travellingnut'tofrotate about the output shaft: Y Y

Assuming theV outputfshaftto be stationary, the travelthe continuouslyrotating collar 16 and will move along` the output shaft axially thereofdue .toits'threaded relationship therewith untilY lug 41Yengageslug.42.' .When '55 this` occurs, vnut .42 has reached thelimit of itstravel to the Sincepthe 'nut cannot rotate, the vdiameter of the spring.decreases, ile. contracts and pulls away from engagement with surfaeev2f3fof collar 16 and surface, 27 yof extensionY 26, as shown in Fig.Y2. Therefore, they continuously rotating collar 16 is'no longer coupledtogrotate bushing ,722', Y

hollow shaft 21 and housing 43. i'At thisv time, vstorage spring 50 iscompletelywound.V f

As theoutpu't shaft is intermittently permitted to rotate to performsome desired work function, the travelling nut 32 is caused to moveaXially'to the right, as seen in V'Fig'.i'l. When lug41.drops off lug42, the nut 32 is permitted'to a rotate vin the direction in which VitVis urged bythe linger on.thehelical,springaclutch.29.- `This permits theportion of'thespringV clutch. adjacent. the'iinger toexparid until itagain engagesV Vsurface 2S` ofthe .continuouslyrotating rewindingoperation of the.:

connected to the cylindrical Vportion Y45 of the housing by v means of arivet .51 andtherother end secured to the env a a Let is be assumed thatthe apparatus is disposed as shown inFig. l. Under these circumstances,thespiral so ling nutwill rotate at the same revolutions per minute as.

Y Y Y Y y However, finger 3,0 on the. helical spring clutch 29 continuesto urge the nut torotate.' .n

i tive'thereto and for axialfmo'vement alongsaid'` ouput l 10 designingthe relationship between input r.p.m.Y and the combination of Ymaximaloutput r.p.m. and time interval, the above limitation must be kept inmind. The present invention s compact, small iin size, and provides ahigh acceleration starting torque.

15 VWhile there have been shown and described and pointed out Vthefundamental novel features of the invention as applied to a preferredembodiment, it will be understoodV that various omissionsv andVsubstitutions and changes in the form and details of the deviceillustrated 20 land in its operation may be made by those skilled intheL art, without departing from the spirit of the invention.V It.

is the intention, therefore,.to be limited only as. indicated by thescope of the following claims.

What is claimed is:

5 l. Spring drive apparatus comprising frame means having aninput shaftjournalled therein which is adaptedto be. continuously rotated, a hollowrotatable member. journalled in said frame means, a threadedoutputshaft: journalled in saidframe means; said input shaft, said.

30 hollow rotatable memberand said output shaft being cond centricallyarranged; a storageV spring having one end connected to said outputshaft yand the other end conf nected to said hollow rotatable member, asleeve mounted in said hollow rotatable memberand threadingly mounted`onsaid output shaft, and clutching means governed byvv member to saidinput shaft.

v 2. Spring drive apparatus comprising frame means. having an inputshaft journalled therein which is adapted.

to be continuously rotated, a hollow' rotatable member journalledin saidframe means, a threaded output shaftv journalledinsaid frame means; saidinput shaft, said.

hollow rotatable member and Vsaid output shaft being concentricallyarranged; a storage spring having one end connected to. saidv outputshaft andthe other end connected to said hollow rotatabley member, asleeve mounted inV saidV hollow rotatable member' and threadinglymountedy on said output shaft, expandable'springY clutch Vmeansadaptedto engage andthereby'clutchvsaid input shaftzand Vsaid'hollow rotatablemember together, and..

means on said sleeve adapted to engage onel endvof said springclutchVmeans when saidfstorage spring is' wound. L for declutching said clutchmeans. Y Y

A.3.. Spring` drivev apparatus Vcomprising frame means having-an inputshaft journalled therein which is adaptedjournalled in -said framemeans, a threaded output shaft journalled .in said frame means; 'saidinput shaft,'said hollow rotatablememberandrsaidoutput shaft `beingconceutricall'y arranged.; a storagespring having one endconnected'tosaid output-shaft and the other end con- *nected to saidhollow rotatable member, a sleeve mounted in said hollowrotatable'memberand threadingly mounted yonazsrarid output shaft, said sleeve being`mounted in said l'nlllow'r.rotatable.memberl for` limited rotationrelavshaft injzone direction by rotation of the output shaftfand :in theopposite direction-,by rotation ofsaid hollow' rotatable member, Y,andclutching means? governed bysaid ber.torsaid-inpnitshaft.r

v V4. Spring. -digive-apparatus comprising frame.' means: havingian1inputshaft vjourrialled therein1whichis adapted, rotatable member.,

' to'l l;n=,continuously` rotated,-=.a. hollow Y Y Y jonrnalledvinfsad,frame means, athreaded output shaft:

said sleeve for intermittently (connecting said rotatableto becontinuouslyrotated, a hollow rotatablememberi sleeve for-intermittentlyconnecting ysaid rotatable memjournalled in said frame means; said inputshaft, said hollow rotatable member and said output shaft beingconcentrically arranged; a storage spring having one end connected tosaid output shaft and the other end connected to said hollow rotatablemember, a sleeve mounted in said hollow rotatable member and threadinglymounted on said output shaft, said sleeve being mounted in said hollowrotatable member for limited rotation relative thereto and for axialmovement along said output shaft in one direction by rotation of theoutput shaft and in the opposite direction by rotation of said hollowrotatable member, an expansible spring having one end secured to saidrotatable member, the other end of said expansible spring being adaptedto be engaged by said sleeve, said expansible spring being mounted to beclutched to said input shaft when it is allowed to expand and to bedeclutched from said input shaft when it contracts, said sleeve havingmeans for engaging said frame means and causing said spring to contractwhen said sleeve reaches the limit of axial movement in one direction, apredetermined further rotation of said output shaft causing said sleeveto be disengaged from said frame means so as to allow said spring toexpand.

5. Spring drive apparatus comprising frame means having an input shaftjournalled therein which is adapted to be continuously rotated, a hollowrotatable member journalled in said frame means, a threaded output shaftjournalled in said frame means; said input shaft, said hollow rotatablemember and said output shaft being eoncentrically arranged; a storagespring having one end connected to said output shaft and the other endconnected to said hollow rotatable member, a sleeve mounted in saidhollow rotatable member and threadingly mounted on said output shaft,said sleeve being mounted in said hollow rotatable member for limitedrotation relative thereto and for axial movement along said output shaftin one direction by rotation on the output shaft and in the oppositedirection by rotation of said hollow rotatable member, an expansiblespring having one end secured to said rotatable member, the other end ofsaid expansible spring being adapted to be engaged by said sleeve, saidexpansible spring being mounted to be clutched to said input shaft whenit is allowed to expand and to be declutched from said input shaft whenit contracts, the reaching of a limit of axial movement of said sleevein one direction causing said sleeve to rotate with respect to saidhollow rotatable member from one limit to the other so as to contractsaid spring, said sleeve being urged to rotate with respect to saidhollow rotatable member back to said one limit after a predeterminedamount of rotation of said output shaft.

References Cited in the file of this patent UNITED STATES PATENTS

